Bacterial outer membrane vesicles in the fight against cancer

Abstract

Bacterial outer membrane vesicles (OMVs) are diminutive vesicles naturally released by Gram-negative bacteria. These vesicles possess distinctive characteristics that attract attention for their potential use in drug administration and immunotherapy in cancer treatment. Therapeutic medicines may be delivered via OMVs directly to the tumor sites, thereby minimizing exposure to healthy cells and lowering the risk of systemic toxicity. Furthermore, the activation of the immune system by OMVs has been demonstrated to facilitate the recognition and elimination of cancer cells, which makes them a desirable tool for immunotherapy. They can also be genetically modified to carry specific antigens, immunomodulatory compounds, and small interfering RNAs, enhancing the immune response to cancerous cells and silencing genes associated with disease progression. Combining OMVs with other cancer treatments like chemotherapy and radiation has shown promising synergistic effects. This review highlights the crucial role of bacterial OMVs in cancer, emphasizing their potential as vectors for novel cancer targeted therapies. As researchers delve deeper into the complexities of these vesicles and their interactions with tumors, there is a growing sense of optimism that this avenue of study will bring positive outcomes and renewed hope to cancer patients in the foreseeable future.

Keywords: Bacterial outer membrane vesicles; Immunotherapy; Nanoparticle; Phototherapy; Tumor microenvironment.

Figure 1

Gram-negative bacterial outer membrane vesicle structure and content.

Figure 2

Mechanisms of entry of OMV into host cells. OMV: Outer membrane vesicle.

Figure 3

Targeted delivery of therapeutic medications involves using OMVs. One approach involves engineering OMVs to encapsulate precise therapeutic compounds, enabling targeted delivery to the desired location. This strategy has the potential to enhance the effectiveness of these medicines while minimizing the likelihood of adverse reactions. OMVs may be engineered to include a mix of immunomodulatory molecules and tumor antigens, eliciting a synergistic effect that augments the immune response and facilitates the destruction of tumor cells. This approach can revolutionize cancer therapy by providing a more efficient and targeted DDS that can potentially overcome the limitations of tumor immunosuppressive microenvironments and drug resistance. AuNPs: Gold nanoparticles; mRNA: Messenger RNA; pre-miRNA: Precursor-micro RNA; siRNA: Small interfering RNA; DDS: Drug delivery systems; OMVs: Outer membrane vesicles.